There are many different proposals in the prior art for concrete form work and assembly or its components, either manually or with some degree of automation, into functional units for concrete construction. Apparatus of various forms has been suggested to facilitate the positioning of concrete form panels for the specialized situation required in the casting of an inside corner that is to form a part of a concrete wall structure. The necessity for inside corner concrete casting obviously arises in the construction of concrete shafts for elevators, stairwells and, indeed, many other tubular concrete structures such as box culverts, etc.
It is important in the casting of inside corners, as well as other concrete structures, to achieve a smooth surface free from joint lines once the form panels and associated components are stripped from the hardened cast concrete. Similarly, it is important that the concrete casting apparatus that is utilized be of as simple construction as possible, involving a minimum number of structural elements and certainly avoiding the necessity for use of a variety of detachable or detached elements which would be readily subject to becoming separated or lost from the overall apparatus such as to prevent reuse of the apparatus at a multiplicity of different site locations.
Many of the prior art apparatus assemblies have been unable to achieve the above explained desired attributes of providing a unitized apparatus which can be automatically operated simply and effectively in the casting of inside surfaces of a concrete corner. Such simple and effective automatic operation necessarily involves both setting up the form panels and related components preliminary to concrete pouring and thereafter the stripping of these panels and components from the hardened concrete structure.
A principal object of this invention is to provide a form unit usable to cast the inside surfaces of a corner which is capable of forming smooth inner surfaces at and adjacent the inside corner with the form unit being effectively automatic both in setting up and in stripping the form panels and components against which concrete is poured.
Another significant object of the invention is to provide a unitized concrete form unit for inside corner casting which is self-contained so that all elements making up the form unit may be automatically manipulated, essentially without independent support for any of the elements making up the concrete form unit.
It is a further object of the instant invention to provide an inside corner form unit which is totally automated, simple in construction with a minimum of interrelated components and is easily subject to being operated hydraulically by means of any suitable hydraulic pressure source.
An additional object of this invention is to provide an inside corner form unit wherein automated operation enables the unit to be set up for initial concrete pouring followed by stripping the form panels disposed adjacent the inside corner and a corner member from the cast inside corner, all of the components making up the form unit being integrated into a unitary assembly wherein the components are tied together generally in a circular or ringlike arrangement with the actuator for the form unit acting diametrically within this ring-shaped integrated assembly of components.